Ultra-wideband (UWB) modulation provides high data rate radio communications for transferring data using very wide modulation bandwidths. FIG. 1 shows a typical application of UWB communication links used for indoor wireless communications. Several transceivers, for example, transceivers 110, 120, 130, 140 are networked allowing high bandwidth communications between the transceivers 110, 120, 130, 140. The transceivers 110, 120, 130, 140 can include, for example, a high definition television (HDTV) monitor networked with other devices, such as, a digital video recorder (DVR), a digital video disk (DVD) player and a computing device.
The Federal Communications Committee (FCC) has mandated that UWB radio transmission can legally operate in the frequency range of 3.1 GHz to 10.6 GHz. The transmit power requirement for UWB communications is that the maximum average transmit Effective Isotropic Radiated Power (EIRP) is −41.25 dBm/MHz in any transmit direction. The bandwidth of each transmission channel is 528 MHz.
To provide optimal operating performance, transmitters and transceivers typically need to be calibrated. For example, transmitters typically suffer from transmitter local oscillator (LO) feed through which needs to be calibrated to minimize its effects, and in some cases, meet FCC requirements. Typical transmitter calibrations include an LO feed through calibration, an output power calibration and filter tuning calibrations.
It is desirable to perform the calibration while the transmitter is in a normal operating mode. That is, it is desirable that the transmission chain remain similar operationally as when it is transmitting, ensuring the calibration is accurate.
It is desirable have a method and apparatus for ensuring signal power of a transmitter does not exceed a threshold average power during calibration of the transmitter.